Steam automatic dispensing device for preparing hot and/or frothed drinks

ABSTRACT

A steam automatic dispensing device for preparing hot and/or frothed drinks, includes a first duct ( 13 ) for introducing steam inside a drink; a second duct ( 15 ) for introducing air inside the drink; an electronic control unit ( 51 ) for controlling the introduction of steam and/or air through said first and second duct, the control unit being programmable to carry out a predetermined control cycle depending on the desired drink to be obtained and on the drink temperature.

BACKGROUND OF THE INVENTION

A. Field

The present invention refers to a steam automatic dispensing device forpreparing hot and/or frothed drinks.

B. Related Technology

Preferably, but not exclusively, the invention is employed as anaccessory separated or integrated of the espresso coffee machine forbar, for producing frothed hot milk to be used for instance forpreparing cappuccinos.

It is known that, for producing milk froth with espresso coffeemachines, the operator uses a container within which he pours a certainamount of milk, inside which he introduced steam through a jetsimultaneously shaking the container, so to generate a certainturbulence inside the milk and to add in the environment air needed forproducing froth.

The qualities and the quantity of the produced froth depend on the waythe milk is shaken and on the amount of steam introduced, and they aretherefore linked to the sensibility and experience of each operator. Itfollows that such features, and then the ones of the cappuccino withinwhich the frothed milk is used, vary from operator to operator and theycan be completely unsatisfactory to the client even deemed to beexcellent by the operator.

A solution to the problem of how making the quality of the obtainedproduct independent from the operator is the subject of theinternational patent application WO 01/97668, in the name of theapplicant. Such patent application discloses a device essentiallyconsisting of a container within which milk to be heated and to befrothed can be poured, inside which are provided a first duct forintroducing steam in milk and a second duct, joined to said first duct,for introducing in milk the air needed for producing froth. The duct forsteam dispensing is provided with a radial opening for the exit of steamand the duct for air ends within an axial opening placed in front ofsaid radial opening of the steam duct. This way, the steam dispensingfrom said radial opening produces a depression that in its turn causesthe air suction through the corresponding duct, the steam effusionvelocity generates a turbulence at the bottom of milk causing that it isheated and mixed with air and a milk-air-steam mixture is thereforeproduced directly inside milk, with consequent froth formation.

However effective, the device above illustrated proves to be not muchversatile, because it always provides the production of a milk-air-steammixture and it makes impossible, for instance, the production of hotmilk without froth.

Other devices using steam for heating drinks or food are respectivelydescribed in the documents U.S. Pat. No. 6,099,878 and FR 2 824 249.

U.S. Pat. No. 6,099,878 discloses a fully automatic, milk inclusiveespresso coffee machine which includes coffee bean grinding and brewingapparatus and a milk aeration system which pumps a selection of milkfrom an internal refrigerator through a choice of aeration processes toa steaming apparatus for heating and further conditioning the milk forjoining the brewed coffee liquor. With each beverage production cycleall milk is hygienically either served or returned to its refrigeratedreservoir. A process is disclosed which includes pumping milk, all in arefrigerated environment, selectively along a plurality of milk linesone of which may inject air for foaming the milk to a steam deliveryline for heating and steaming it and delivering it to a beverage cup.After the desired amount of milk has been delivered, the steam flowcontinues momentarily to cleanse the line of residual milk. FR 2 824 249discloses a device for heating food comprising a temperature measurementrod including an agitator section with steam outlets and temperaturesensor. A handle is used for stirring. The steam generator feeds theoutlets through a flexible tube connected to the rod. An electricalcontroller is wired to the sensor and steam generator and/or a displayunit.

BRIEF SUMMARY OF THE INVENTION

It is the main object of the present invention to realise a device forheating and/or preparing froth of a liquid that allows to automaticallyobtain different kinds of drinks, such as for instance, hot milk, hotand frothed milk, infusions, etc.

Another object of the present invention is to realise a device forheating and/or preparing froth of a liquid having limited size, that canbe easily used in association with a professional coffee machine.

A further object of the present invention is to realise a device forheating and/or preparing froth of a liquid that allows to control thetemperature of the liquid to be heated.

These and other objects are achieved with the automatic device forheating and/or preparing froth of a liquid as claimed in theaccompanying claims.

By following the teachings of WO 01/97668, the device according to theinvention comprises a first duct to introduce steam and a second ductthrough which it is possible to introduce air inside a liquid to beheated in order to obtain the formation of froth.

Advantageously, according to the present invention, each of said ductsis connected to an electrovalve: the user can select the kind of wanteddrink and, on the basis of said selection, a microprocessor controls theopening and the closing of said electrovalves, so to permit or preventaccording to a preset cycle the introduction of air and steam in thedrink.

Said microprocessor can be equipped with a storage within which aplurality of operating cycles are stored, corresponding to a pluralityof drinks that can be prepared with said device. Each of said operatingcycles provides a sequence of steps of preset duration of opening andclosing of each valve.

Advantageously, the device according to the invention can furthercomprise a sensor for measuring the temperature, so to control thetemperature of the liquid to be heated and/or frothed and, in case, tocorrect the parameters of the above-mentioned operating cycles in orderto obtain a drink at the desired temperature.

DESCRIPTION OF THE DRAWINGS

A preferred embodiment of the invention will be now described in detailwith particular reference to the attached drawings, supplied as nonlimiting example, in which:

FIG. 1 is a schematic side view of the ducts dispensing steam and air ofthe device according to the invention;

FIG. 2 a is a scheme of a first embodiment of the device according tothe invention;

FIG. 2 b is a scheme of a second embodiment of the device according tothe invention;

FIG. 3 is a block diagram of the electronic control unit of the deviceaccording to the invention;

FIG. 4 is a graph showing the opening and closing steps of the valves inan example of preparing cycle of a drink.

DETAILED DESCRIPTION

With reference to FIG. 1, an embodiment of the device according to theinvention is shown that comprises a first duct 13 for steam and a secondduct 15 for air. In the example shown said ducts are immersed into theliquid, for instance milk, contained inside a container 11.

The steam duct 13 has the lower end 13a closed and it is provided, nearsaid end, with a radial hole 17. The air duct 15, having a diametersmaller than one of the steam duct, has the end portion 19 tapered andit ends with an axial opening 21, placed in front of said radial hole 17of said steam duct 13.

A temperature electronic sensor 23, fit for measuring the temperature ofthe liquid to be heated, is further fastened to one of said ducts 13,15. Said sensor 23 is electronically connected to an electronic controlunit through a couple of conductors passing inside a protective sheath25.

In FIG. 2 a a first embodiment of the hydraulic circuit of the deviceaccording to the invention is shown.

The air duct 15 is provided with a first three-way electrovalve 16,whose remaining two ways are connected one to the outside environmentthrough a suction pipe 33 that has the end 35 open and the other to asecond three-way electrovalve 14 through an intermediate pipe 31.

The remaining two ways of said second electrovalve 14 are in their turnconnected one to said steam duct 13 and the other to a steam source 27through a dispensing pipe 29.

In such way, according to the opening or closing condition of saidelectrovalves 14, 16 one and/or the other of said ducts 13, 15 can beput in communication with said steam source 27 or with the outsideenvironment.

In particular, thanks to the intermediate pipe 31 that connects the twoelectrovalves 14, 16, it is possible to introduce steam into the liquidto be heated through both said ducts 13, 15, or, alternatively, tosimultaneously introduce into said liquid steam through duct 13 and airthrough duct 15.

Advantageously, thanks to the above-mentioned expedient it is possibleto obtain drinks that require different preparation modes.

For instance, in case said second electrovalve 14 is positioned so toput in communication the steam dispensing pipe 29 both with theintermediate pipe 31 and with the steam duct 13 and said firstelectrovalve 16 is positioned so to put in communication theintermediate pipe 31 with the air duct 15 and to close said suction pipe33, the steam generated from said steam source 27 will reach both theducts 13, 15 and the liquid will be heated, substantially without frothformation.

In case, on the contrary, said first electrovalve 16 is positioned so toclose the intermediate pipe 31 and to put in communication the suctionpipe 33 with the air duct 15, the steam generated from said steam source27 will only reach the steam duct 13, while the air duct 15 will bereached by the air sucked from the outside environment and it will betherefore obtained the froth formation during the liquid heating.

It is evident that, with the device according to the invention, it ispossible to set numerous operating cycles based on the sequence of aplurality of steps, each characterised by a set duration and by adifferent condition of opening/closing of said electrovalves 14, 16,correspondingly obtaining numerous preparation modes of differentdrinks.

It is to be noted that, in a preferred embodiment, said steam source 27consists of a steam jet of an espresso coffee machine for bar and, tothis purpose, said pipe 29 can be equipped with means to be tightfastened to said steam jet.

Alternatively, the device according to the invention can be providedwith an autonomous steam generator and it can therefore be usedindependently from other apparatuses for bar.

With reference to FIG. 2 b a second embodiment of the device accordingto the invention is shown. In said second embodiment the first three-wayelectrovalve 16, instead of being connected through the intermediatepipe 31 to the second three-way electrovalve 14, is directly connectedthrough a pipe 37 to the pipe 29 carrying steam from the source 27 tothe second electrovalve 14 (alternatively, pipe 37 could be connected toduct 13 immediately downstream the second electrovalve 14 as shown inFIG. 2 b with the dotted line). In such way, the second three-wayelectrovalve 14 can be advantageously equipped with a pipe 39 open tothe outside at 43 in order to allow the downwards easy flow by gravityof the liquid in case present in the duct 13 that, otherwise, shouldtend to clog, when said second valve 14 is positioned so to allow thepassage from pipe 41 to duct 13.

It is to be noted that in the shown examples two three-way electrovalveshave been employed for reasons of simplicity and economy, but it will bealso possible to provide arrangements that employ a combination of otherkinds of electrovalves and connections.

FIG. 3 is a block diagram that illustrates in a simplified way theelectronic control unit 51 of the device according to the invention.

Said control unit 51 comprises a selector 53 onto which the user canselect the kind of wanted drink. The selection carried out onto theselector 53 controls a microprocessor 55, provided with a storage 57,within which the data relevant to the operating cycle corresponding toeach possible user's selection are stored.

On the basis of the instructions stored inside the storage 57 saidmicroprocessor 55 performs a cycle based on a sequence of opening andclosing steps of each electrovalve 14, 16.

Said microprocessor 55 is further connected to the temperature sensor23, if this is present. On the basis of the temperature-indicativesignal sent by said sensor 23, the microprocessor 55 can modify theduration of the different steps of the opening and closing cycle of theelectrovalves stored inside the storage 57 in order to obtain a drinkwith the optimum temperature and froth amount.

As an example, in FIG. 4 is reproduced a graph that illustrates theoperating cycle of the device according to the invention in case ofpreparing a cappuccino.

In said graph, on the axis of abscissae the time for preparing the drinkis quoted and on the axis of ordinates the milk temperature is quoted.

During a first step 1, shown with a dotted line in the graph, said firstelectrovalve 16 and said second electrovalve 14 are maintained in such aposition to simultaneously send steam to both the ducts 13 and 15 and toprevent air entering through the suction pipe 35.

When milk reaches a preset temperature T1, for instance about 35° C. (orafter a fixed time when the temperature control is not present), in asecond step 11, shown with a continuous line in the graph, the firstelectrovalve 16 is positioned so to allow the air entering through theduct 15 and to prevent steam passing from the intermediate pipe 31.

Said first electrovalve is maintained open up to a preset temperature T2(or for a fixed time when the temperature control is not present), forinstance of 5° C. under the final wanted temperature T3 (in the example65° C.).

Once reached said temperature T2, in a third step III, shown with adot-point line in the graph, said first electrovalve 16 is againpositioned so to allow the steam entering also through duct 15 and toprevent air suction through the suction pipe 35.

This arrangement is maintained until the preset temperature T3 isreached, having reached which the second valve 14 is closed so toprevent steam introduction into both the ducts and to allow the removalof the drink.

Though in the preferred embodiment the ducts of the device according tothe invention are directly connected to the steam jet of a professionalespresso coffee machine, by following the teachings of WO 01/97668 itwill be possible to provide a device comprising a container for theliquid to be heated, wherein said ducts are fastened to said container.

1-12. (canceled)
 13. A steam automatic dispensing device for preparingdrinks exemplified by hot and frothed drinks, comprising: a first ductfor introducing steam inside a drink; a second duct for introducing airinside said drink; an electronic control unit for controlling theintroduction of either or both steam and air through said first andsecond duct, said control unit being programmable to carry out apredetermined control cycle depending on the desired drink to beobtained, said first and second duct being provided withelectromechanical means for controlling the introduction of either orboth steam and air through said ducts and said electromechanical meansbeing operated by said electronic control unit, wherein saidelectromechanical means comprise a corresponding electrovalve for eachof said first and second duct for controlling the introduction of steamand/or air through said ducts and wherein a first of said twoelectrovalves is a three-way electrovalve, a first way being connectedto said second duct, a second way being connected to an air introducingpipe and a third way being connected to a steam dispensing pipe.
 14. Adevice according to claim 13, wherein a second of said two electrovalvesis a three-way electrovalve, a first way being connected to said firstduct, a second way being connected to a steam dispensing pipe and athird way being connected to said third way of said first three-wayelectrovalve through an intermediate pipe.
 15. A device according toclaim 13, wherein a second of said two electrovalves is a three-wayelectrovalve, a first way being connected to said first duct, a secondway being connected to a steam dispensing pipe and a third way beingconnected to a pipe open to the outside.
 16. A device according to claim13, wherein said first duct has a closed end fit for being immersed insaid drink and it is provided with a radial hole near said end.
 17. Adevice according to claim 16, wherein the end fit for being immersed insaid drink of said second duct is provided with an axial opening locatedso to be in front of said radial hole of said first duct.
 18. A deviceaccording to claim 13, wherein said electronic control unit comprises amicroprocessor, provided with a memory containing instructions relevantto an opening and closing cycle of said electrovalves are stored, saidmicroprocessor controlling opening and closing of said electrovalves onthe basis of said instructions.
 19. A device according to claim 18,wherein said memory contains the instructions relevant to the carryingout of a plurality of opening and closing cycles of said electrovalvesand wherein said electronic control unit comprises a selector to selectthe wanted cycle.
 20. A device according to claim 19, including atemperature detecting electronic probe fit for being immersed in saiddrink, said probe generating a temperature-indicative signal that isprocessed by said microprocessor for controlling opening and closing ofsaid electrovalves.
 21. A device according to claim 19, wherein saidopening and closing cycle provides a first step wherein steam isintroduced simultaneously through both said first and second duct andthe introduction of air is prevented, a second step wherein steam isintroduced through said first duct and air is introduced through saidsecond duct and a third step wherein steam is introduced simultaneouslythrough both said first and second duct and the introduction of air isprevented.
 22. A device according to claim 21, wherein said first secondand third steps have a pre-set duration.
 23. A device according to claim20, wherein the duration of said first, second and third steps dependson the temperature signal coming from said temperature probe.
 24. Adevice according to claim 13, further comprising a container suitablefor containing said drink, said first and second duct being fastened tosaid container.